pg_test_fsync

Name

pg_test_fsync -- determine fastest
wal_sync_method for PostgreSQL

Synopsis

pg_test_fsync [option...]

Description

pg_test_fsync is intended to
give you a reasonable idea of what the fastest wal_sync_method
is on your specific system, as well as supplying diagnostic
information in the event of an identified I/O problem. However,
differences shown by pg_test_fsync might not make any significant
difference in real database throughput, especially since many
database servers are not speed-limited by their transaction logs.
pg_test_fsync reports average
file sync operation time in microseconds for each wal_sync_method, which can also be used to inform
efforts to optimize the value of commit_delay.

Options

pg_test_fsync accepts the
following command-line options:

-f--filename

Specifies the file name to write test data in. This file
should be in the same file system that the pg_xlog directory is or will be placed in.
(pg_xlog contains the
WAL files.) The default
is pg_test_fsync.out in the
current directory.

-s--secs-per-test

Specifies the number of seconds for each test. The more
time per test, the greater the test's accuracy, but the
longer it takes to run. The default is 5 seconds, which
allows the program to complete in under 2 minutes.